The invention relates to a self-propelled milling machine and a method for controlling a self-propelled milling machine in accordance with claims as submitted herewith.
The self-propelled milling machine, specifically, road milling machine, surface miner or recycler, comprises a machine frame with a longitudinal axis, a chassis with wheels or tracked ground-engaging units which support the machine frame, as well as a controller for the travelling and milling operation and a height-adjustable working drum. A slewable last or single transport conveyor of specified length is arranged in front of or behind the working drum as seen in the direction of travel of the milling machine, where said transport conveyor is slewable automatically about, as a minimum, an essentially vertical first axis laterally under a slewing angle. Such milling machines are known from EP 2 700 748.
The milling machine comprises a controller for the travelling and milling operation, as well as a working drum for the milling of, for example, a road pavement. A transport conveyor device comprising, as a minimum, one transport conveyor is located in front of or behind the working drum as seen in the direction of travel. Depending on where the transport conveyor is arranged, the milling machine is in the following called a front-loading/rear-loading milling machine. The transport conveyor may be slewed, relative to the longitudinal axis of the milling machine, laterally under a specifiable slewing angle to the left or right and may be adjustable in height via a specifiable elevation angle. The transport conveyor comprises a discharge end at which the milling material is unloaded, due to the conveying speed and the elevation angle, onto the loading surface of a transport vehicle via a flight path in the form of a parabolic trajectory.
A problem consists in the fact that the operator of the milling machine also needs to control loading of the loading surface by adjusting the slewing angle, the elevation angle, where appropriate, and/or the conveying speed of the transport conveyor and, by doing so, is distracted from the actual task of carrying out the milling operation. A correction of the slewing angle may be required, for example, when altering the direction of travel of the milling machine or of the transport vehicle.
In case of a rear-loading milling machine, problems also arise in coordinating the milling machine with the transport vehicle especially since the transport vehicle needs to drive behind the milling machine in reverse travel. An even higher level of stress results for the operator of the milling machine as he needs to control the milling process in forward travel on the one hand and needs to monitor loading of the transport vehicle behind the milling machine as seen in the direction of travel on the other hand, and in the process needs to control mainly the slewing angle and the elevation angle, where appropriate, and/or the conveying speed of the transport conveyor device.
The transport conveyor may be longer than the actual milling machine and usually measures approx. 5 m to approx. 8 m in length.
An automatic control of the slewing angle is specified from EP 2 700 748 which enables the operator of the milling machine to concentrate on the milling operation and on driving along a specified milling track. The milling machine can thus be moved in the direction of travel similar to a vehicle with a towed single-axle trailer.